Dishwasher gurgling through sink

I was at my in-laws new lake house and we turned on the dishwasher. I was in another room watching tv and began hearing a loud gurgling noise. I went into the kitchen to discover the noise coming out of the drains in the kitchen sink. I looked underneath to see how the builder hooked up the dishwasher and I see why there is so much noise, as the incoming drain empties into the crossover piece between the sink bowls.

Is this the proper way to bring the drain line in? The drain line is brought up high in an arc to prevent drain backflow. But, this is awfully noisy especially in this house with a very large kitchen, all granite tops, hardwood floors, and 12 foot ceilings. It simply echoes around the main floor.

Here is a photo of the way it is hooked up. There is no access underneath the floor to the drain line as the ceiling below is finished drywall.

The difference I see in that photo is that the incoming dishwasher drain hose is brought into the vertical tailpipe off the sink basket. I do not follow how that is going to remove the gurgling noise. Any explanation from anyone?

These issues really bother. The builder is dragging it's feet to finish the punch list and I keep finding these small problems. This dishwasher is an Asko brand. I was surprised to hear how noisy it is, and now my in-laws are concerned. I told them I would try and figure out what is going on, but I told them I am pretty sure it is an installation mistake causing the noise and not the dishwasher.

I didn't think about the plastic strainers when I took the picture, but you are right, I would prefer to see brass under there. The sink is also a nice undermount sink, but the strainers up top are a nice dark bronze. I haven't seen a strainer with metal top and plastic bottom before.

Yes its got the cheapo AAV but a dishwasher tailpiece is mounted on the house side of the trap therefore water falling to the trap will be heard. The level of sound will vary depending on the height of the fall.

If you don't like to hear it close the sink stoppers and it will go away.

The sound of the water is coming out of the second drain. There is nothing "wrong" with your connection, but if it were connecte to the vertical pipe over the trap it would probably mask a lot of the sound coming out of the drain. The AAV should only be functioning when the drainage stops.

I understand that with this set-up, there will be noise. It is possible to not have any noise, so the statement that a dishwasher's pump will always cause noise is not true. For example, my dishwasher drain line is run through the floor into it's own trap before it connects to the 3" horizontal drain that is also drains from the sink. With this setup, there is no noise coming through the sink.

With not being used to hearing any of the water being pumped out, I found this to be extremely loud and annoying. As I mentioned before, it is a large kitchen with lots of granite, hardwood floors, and no fabric to absorb any sound, so it really echoes around and the sound is heard in adjoining rooms.

Is the only solution for this setup is to remember to plug the strainers when the dishwasher is on in order to not hear the pump noise?

Course you could always rip her out an put in a Miele. They are whisper quiet. Hard on the wallet though. The other thing you can do is get the wife to wash them by hand, that might quieter Then again, maybe not

I hope it's not a problem opening an old thread, think this is better than creating a new one?

I have a similar problem with gurgling coming from the sink. Having an open plan house makes this a problem.

The dishwasher hose is grey, attached the the vertical pipe just before the trap. This was coming in from the side (90 degrees to the bend) so I just changed it to see if this helps.

The only solution I can think of is to change the bend (circled in red in second picture) and place a t-connector in it's place and run a pipe up to just under the worktop with a cap that allows air in (if this would work I can then muffle the sound in the sink somehow).

I will also try closing the traps, but assume the noise will just come out of the overflows instead.

Any other suggestions would be gratefully received. We had this problem with our 10 year old Bosch and the same with the new one which runs even quieter except for the gurgling drain.

A dishwasher draining will gurgle.
You don't show a vent for the p-trap. Those tend to siphon without a vent. Plumbed this way, we would at least install an AAV after the p-trap, and loop the dishwasher drain as high as possible under the counter before connecting to the tee that you have. That would prevent sink waste from backing up into the dishwasher.

Studor Vent

We would have this vent on the top side of the gray 90.
That should be a tee, with the vent on the top side of the tee.

Thanks for your reply. The grey pipe connects into a bigger (5 inch? ) pipe in the wall which is vented so I'm not sure if I need to add another vent under the sink.

Click to expand...

That is somewhat similar to some of the East Coast plumbing in the US where the vent takes off below the floor on an S trap. That part should be okay then.
Then what you have, is pretty normal. I can always tell when the dishwasher is draining in my home too.